Wearable electronic devices have become increasingly advanced, and it is commonplace to use such devices when exercising to monitor certain metrics related to a particular exercise. For example, a runner may wear an electronic device that measures calories burned and the overall distance of a run. For exercises such as running and cycling, methods exist for measuring power exerted by the user during the exercise (i.e., calories burned). For example, partial power generated by a runner can be calculated by determining the energy consumed when raising the runners center of mass each step and moving forward. Therefore, the power exerted while running can be calculated as a function of vertical acceleration, and the user's mass, and each of these components of the calculation can be easily obtained with simple sensor measurements or using information provided by the user.
However, the calculation of power generated by the user is more complex for other types of activities, such as skiing. For instance, the force exerted by the skier while skiing is not the result of the skier raising his center of mass to overcome gravity, but rather in propelling or “pushing” himself forward on what is often uneven terrain. Therefore, determining power generated by a skier while skiing presents several challenges.